CN108723287B - Thermal regeneration method of silicate inorganic coating wet waste sand - Google Patents
Thermal regeneration method of silicate inorganic coating wet waste sand Download PDFInfo
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- CN108723287B CN108723287B CN201810597043.0A CN201810597043A CN108723287B CN 108723287 B CN108723287 B CN 108723287B CN 201810597043 A CN201810597043 A CN 201810597043A CN 108723287 B CN108723287 B CN 108723287B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/04—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by grinding, blending, mixing, kneading, or stirring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/06—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by sieving or magnetic separating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
- B22C5/10—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by dust separating
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Processing Of Solid Wastes (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
The invention belongs to the technical field of sand core materials for mold casting, and particularly discloses a thermal regeneration method of silicate inorganic coating wet waste sand, which comprises the following steps: crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; placing the waste sand into a roasting furnace, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 20-80 Kg/min; the temperature of the roasting area of the roasting furnace is controlled at 400-. Through the treatment of the thermal regeneration method, the silicate waste sand can be effectively regenerated and reused, and the problems of environmental pollution and resource waste caused by direct discharge are solved.
Description
Technical Field
The invention belongs to the technical field of sand core materials for mold casting, and particularly relates to a thermal regeneration method of silicate inorganic coating wet waste sand.
Background
Silicate is used as an inorganic chemical binder, has wide sources, low price, no toxicity and no odor, and is widely applied to the casting industry at present. Silicate binders, which are free from toxic gases during their application compared to organic resin binders, are considered as the type of sand most likely to realize green casting today with increasingly stringent environmental standards.
However, the silicate molding sand has the problem of difficult regeneration and reuse, which causes the discharge of a large amount of silicate waste sand, which not only causes serious pollution to the environment, but also causes great resource waste. There are many regeneration and recovery methods for the waste sand, such as mechanical friction regeneration, chemical regeneration, wet regeneration and thermal regeneration, but most of these regeneration and recovery methods are directed at the waste sand of organic resin binder, and because there is a great difference in performance and structure between the organic coated sand and the inorganic coated sand, the effect of recovering and utilizing the inorganic waste sand of silicate by using the existing methods such as wet regeneration, mechanical regeneration and thermal regeneration is not ideal, and the regenerated waste sand cannot be directly reused for casting.
Disclosure of Invention
The invention aims to provide a thermal regeneration method of silicate inorganic coating wet waste sand, which aims to solve the problem of resource waste caused by difficulty in regeneration and reuse of the silicate waste sand.
In order to achieve the purpose, the basic scheme of the invention is as follows: a thermal regeneration method of silicate inorganic coating wet waste sand comprises the following steps: crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; placing the waste sand into a roasting furnace, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 20-80 Kg/min; the temperature of the roasting area of the roasting furnace is controlled at 400-.
The beneficial effect of this basic scheme lies in:
1. the temperature of the roasting area is controlled to be 400-500 ℃, the temperature of a film wrapped on the surface of the waste sand can be instantly heated to 300-400 ℃ when the waste sand passes through the roasting area by controlling the flow of the waste sand, but the internal temperature of the waste sand does not reach the high temperature, when the waste sand falls on the bottom of the roasting furnace, the temperature of the internal part and the external part of the waste sand is about 300 ℃ under the action of heat transfer, and the applicant finds that the waste sand is subjected to heat preservation for 1-2 hours at the temperature, so that the film on the surface of the waste sand can be effectively removed.
2. The heat regeneration treatment method treats inorganic waste sand of silicate, can fully remove moisture on the surface film of the waste sand by roasting, changes the film on the surface from toughness to brittleness, and is beneficial to removing the film.
3. The silicate waste sand is various, sodium oxide and silicon dioxide are contained in common silicate waste sand, the sodium oxide and the silicon dioxide in the silicate have different expansion behaviors at the same temperature, and the sodium oxide and the silicon dioxide in the silicate are easy to fall off when being scrubbed after being expanded by heat. The binder for foundry sand used in aluminum casting is generally a complex silicate binder modified with phosphate or borate, and the film formed by the foundry sand prepared is actually a composite film in which three materials, which have different swelling behaviors even at the same temperature, are embedded with each other, and the film is easily removed after firing.
4. The foundry waste sand contains a certain amount of metallic aluminum scraps, and the oxidation of the metallic aluminum scraps into alumina or aluminate compounds can be promoted in an aerobic environment after the high-temperature calcination, and the alumina or aluminate compounds can form blocks after the substances are accumulated and can be screened and removed after the substances are discharged from a furnace at the later stage, so that the content of the metallic aluminum scraps in the waste sand is effectively reduced.
5. The thermal regeneration method realizes regeneration and reuse of the silicate inorganic tectorial membrane wet waste sand, has good treatment effect, can be applied to tectorial membrane sand, resin sand and the like, and completely or partially replaces new sand for use.
Further, controlling the flow of the waste sand at 40-52 Kg/min; the temperature of the roasting area of the roasting furnace is controlled at 440-470 ℃, the waste sand is kept for 1.25h after reaching the furnace bottom, and the sand is discharged. Through a plurality of tests, the applicant finds that the roasting effect is better when the roasting temperature is controlled within the range.
Further, the mechanical regeneration treatment is carried out on the waste sand before the roasting treatment is carried out on the waste sand, and the method comprises the following steps: and grinding the silicate waste sand subjected to air separation and dust removal for 5-60s, and then removing dust.
Further, the dust removal after the grinding treatment adopts a water separation dust removal mode. The waste sand contains a large amount of dust, and the washing is more favorable for removing the dust attached to the pits of the waste sand, so that the bonding film is exposed on the surface of the sand grains.
Further, a spiral scrubbing machine is selected to carry out water separation dust removal treatment on the waste sand.
Further, after roasting treatment of the waste sand, mechanical regeneration and water regeneration treatment of the waste sand are required, and the method specifically comprises the following steps: grinding the roasted waste sand while the waste sand is hot, performing multistage scrubbing, and performing air separation and dust removal after the multistage scrubbing; the milling time is 10-60s, and the scrubbing grade is 3-9. After the waste sand is roasted, the film on the surface of the waste sand is changed into brittleness from toughness, and sodium oxide and silicon dioxide in the silicate have different expansion behaviors at the same temperature, so that the sodium oxide is easily changed into powder by grinding and scrubbing the waste sand, and the silicon dioxide falls off along with the film coated on the surface of the waste sand, thereby ensuring the effect of regeneration and recovery.
Further, air is blown in during roasting, and the air blowing time is 10-20 min. Blowing air has the following functions of firstly supplying oxygen to the roasting furnace and secondly boiling sand in the roasting furnace, reducing the descending rate of sand grains, prolonging the roasting time and facilitating the surface adhesive film to be fully heated to generate sufficient expansion; and thirdly, blowing off fine powder on the surface of the waste sand.
Further, a regenerative grinding mill is selected to grind the waste sand. The grinding treatment and grinding effect of the regenerative grinding mill on the waste sand is better.
Detailed Description
The following is further detailed by way of specific embodiments:
example 1
A thermal regeneration method of silicate inorganic coating wet waste sand comprises the following steps:
(1) crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; grinding the screened waste sand by a regenerative grinding mill for 45 s; and after the grinding treatment, a spiral scrubbing machine is selected to carry out water separation dust removal treatment on the waste sand.
(2) Putting the waste sand treated in the step (1) into a roasting furnace, controlling the particle size and the adding flow of the waste sand, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 35 Kg/min; controlling the temperature of a roasting area of the roasting furnace at 450 ℃, preserving heat for 1.25h after waste sand reaches the furnace bottom, and discharging the sand; air was blown in during the calcination for 20 min.
(3) And (3) immediately carrying out grinding and multistage scrubbing treatment on the roasted waste sand, wherein the grinding time is 50s, the scrubbing stage number is 6, air separation and dust removal are carried out after multistage scrubbing, and the sand after dust removal is sent into a sand silo.
Example 2
A thermal regeneration method of silicate inorganic coating wet waste sand comprises the following steps:
(1) crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; grinding the screened waste sand by a regenerative grinding mill for 20 s; and after the grinding treatment, a spiral scrubbing machine is selected to carry out water separation dust removal treatment on the waste sand.
(2) Putting the waste sand treated in the step (1) into a roasting furnace, controlling the particle size and the adding flow of the waste sand, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 50 Kg/min; controlling the temperature of a roasting area of the roasting furnace at 480 ℃, preserving heat for 1.4 hours after waste sand reaches the furnace bottom, and discharging the sand; air was blown in during the calcination for 20 min.
(3) And (3) immediately carrying out grinding and multistage scrubbing treatment on the roasted waste sand, wherein the grinding time is 40s, the scrubbing stage number is 5, air separation and dust removal are carried out after multistage scrubbing, and the sand after dust removal is sent into a sand silo.
Example 3
A thermal regeneration method of silicate inorganic coating wet waste sand comprises the following steps:
(1) crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; grinding the screened waste sand by a regenerative grinding mill for 60 s; and after the grinding treatment, a spiral scrubbing machine is selected to carry out water separation dust removal treatment on the waste sand.
(2) Putting the waste sand treated in the step (1) into a roasting furnace, controlling the particle size and the adding flow of the waste sand, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 38 Kg/min; controlling the temperature of a roasting area of the roasting furnace at 430 ℃, preserving heat for 1.8 hours after waste sand reaches the furnace bottom, and discharging the sand; air was blown in during the calcination for 18 min.
(3) And (3) immediately carrying out grinding and multistage scrubbing treatment on the roasted waste sand, wherein the grinding time is 55s, the scrubbing stage number is 5, air separation and dust removal are carried out after multistage scrubbing, and the sand after dust removal is sent into a sand silo.
The acid consumption, the sludge content and the pH value of the reclaimed sand treated in examples 1 to 3 and the wet waste sand of silicate inorganic coated sand not subjected to any processing treatment were respectively detected to obtain Table 1:
TABLE 1
And (4) analyzing and concluding:
according to the data in table 1, the wet waste sand of silicate inorganic precoated sand processed by the technical scheme of the invention has acid consumption value, mud content and pH value far lower than those of wet waste sand of silicate inorganic precoated sand which is not processed, can meet the use standard of regenerated wet waste sand of silicate inorganic precoated sand, can be put into reuse, and effectively reduces the cost.
Claims (6)
1. A thermal regeneration method of silicate inorganic coating wet waste sand is characterized in that: the method comprises the following steps: crushing and sieving the waste sand to ensure that the content of metal chips in the waste sand is below 0.15 percent, and winnowing and dedusting the waste sand to ensure that the content of fine powder in the waste sand is below 5 percent; placing the waste sand into a roasting furnace, controlling the particle size of the waste sand to be less than 6 meshes, and controlling the flow of the waste sand to be 40-52 Kg/min; controlling the temperature of a roasting area of the roasting furnace at 440-470 ℃, preserving the heat for 1.25h after the waste sand reaches the furnace bottom, and discharging the sand; blowing air for 10-20min while roasting.
2. The method for thermal regeneration of silicate inorganic coating wet waste sand according to claim 1, wherein: before roasting treatment is carried out on the waste sand, mechanical regeneration treatment is carried out on the waste sand, and the method comprises the following steps: and grinding the silicate waste sand subjected to air separation and dust removal for 5-60s, and then removing dust.
3. The method for thermal regeneration of silicate inorganic coating wet waste sand according to claim 2, wherein: and the dust removal after the grinding treatment adopts a water separation dust removal mode.
4. The method for thermal regeneration of silicate inorganic coating wet waste sand according to claim 3, wherein: and (4) selecting a spiral scrubbing machine to carry out water separation dedusting treatment on the waste sand.
5. The method for thermal regeneration of silicate inorganic coating wet waste sand according to claim 2, wherein: after roasting treatment of the waste sand, mechanical regeneration and multistage scrubbing treatment of the waste sand are required, and the method specifically comprises the following steps: grinding the roasted waste sand while the waste sand is hot, performing multistage scrubbing, and performing air separation and dust removal after the multistage scrubbing; the milling time is 10-60s, and the scrubbing grade is 3-9.
6. The method for thermal regeneration of silicate inorganic coating wet waste sand according to claim 2, wherein: and grinding the waste sand by using a regenerative grinding mill.
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| CN109226668A (en) * | 2018-11-21 | 2019-01-18 | 合肥仁创铸造材料有限公司 | A kind of inorganic sand regeneration method |
| CN109396328A (en) * | 2018-12-17 | 2019-03-01 | 合肥仁创铸造材料有限公司 | A kind of combining and regenerating technique and the inorganic reclaimed sand of inorganic old sand thermal method and wet process |
| CN109822041A (en) * | 2019-03-27 | 2019-05-31 | 烟台通鼎舟汽车零部件有限公司 | A kind of inorganic antiquated sand regeneration method |
| CN112077260A (en) * | 2020-09-08 | 2020-12-15 | 重庆长江造型材料常州有限公司 | Acid consumption value controllable green sand regeneration and recycling process |
| CN112846070B (en) * | 2020-12-28 | 2022-09-23 | 亚威科技(文昌)有限公司 | Precoated sand recycling and regenerating process and equipment |
| CN115846588B (en) * | 2022-11-17 | 2024-01-12 | 柳晶科技集团股份有限公司 | Regeneration method of foundry inorganic waste sand and regenerated sand |
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| CN102000764A (en) * | 2010-12-17 | 2011-04-06 | 重庆长江造型材料（集团）有限公司 | Chemical regeneration method in casting waste sand disposing process |
| JP2016147287A (en) * | 2015-02-12 | 2016-08-18 | マツダ株式会社 | Casting sand regeneration process, and polishing device |
| JP6354728B2 (en) * | 2015-10-19 | 2018-07-11 | トヨタ自動車株式会社 | Reuse method and reuse device for core sand |
| CN106623767B (en) * | 2016-08-31 | 2018-10-30 | 圣固（江苏）机械有限公司 | A kind of device for precoated sand recycling |
| CN107649643B (en) * | 2017-09-11 | 2019-11-15 | 齐鲁工业大学 | A kind of regenerating used method of selective laser sintering mound precoated sand |
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